1/* 2 * DS1286 Real Time Clock interface for Linux 3 * 4 * Copyright (C) 1998, 1999, 2000 Ralf Baechle 5 * 6 * Based on code written by Paul Gortmaker. 7 * 8 * This driver allows use of the real time clock (built into nearly all 9 * computers) from user space. It exports the /dev/rtc interface supporting 10 * various ioctl() and also the /proc/rtc pseudo-file for status 11 * information. 12 * 13 * The ioctls can be used to set the interrupt behaviour and generation rate 14 * from the RTC via IRQ 8. Then the /dev/rtc interface can be used to make 15 * use of these timer interrupts, be they interval or alarm based. 16 * 17 * The /dev/rtc interface will block on reads until an interrupt has been 18 * received. If a RTC interrupt has already happened, it will output an 19 * unsigned long and then block. The output value contains the interrupt 20 * status in the low byte and the number of interrupts since the last read 21 * in the remaining high bytes. The /dev/rtc interface can also be used with 22 * the select(2) call. 23 * 24 * This program is free software; you can redistribute it and/or modify it 25 * under the terms of the GNU General Public License as published by the 26 * Free Software Foundation; either version 2 of the License, or (at your 27 * option) any later version. 28 */ 29#include <linux/types.h> 30#include <linux/errno.h> 31#include <linux/miscdevice.h> 32#include <linux/slab.h> 33#include <linux/ioport.h> 34#include <linux/fcntl.h> 35#include <linux/init.h> 36#include <linux/poll.h> 37#include <linux/rtc.h> 38#include <linux/spinlock.h> 39 40#include <asm/ds1286.h> 41#include <asm/io.h> 42#include <asm/uaccess.h> 43#include <asm/system.h> 44 45#define DS1286_VERSION "1.0" 46 47/* 48 * We sponge a minor off of the misc major. No need slurping 49 * up another valuable major dev number for this. If you add 50 * an ioctl, make sure you don't conflict with SPARC's RTC 51 * ioctls. 52 */ 53 54static DECLARE_WAIT_QUEUE_HEAD(ds1286_wait); 55 56static ssize_t ds1286_read(struct file *file, char *buf, 57 size_t count, loff_t *ppos); 58 59static int ds1286_ioctl(struct inode *inode, struct file *file, 60 unsigned int cmd, unsigned long arg); 61 62static unsigned int ds1286_poll(struct file *file, poll_table *wait); 63 64void ds1286_get_alm_time (struct rtc_time *alm_tm); 65void ds1286_get_time(struct rtc_time *rtc_tm); 66int ds1286_set_time(struct rtc_time *rtc_tm); 67 68void set_rtc_irq_bit(unsigned char bit); 69void clear_rtc_irq_bit(unsigned char bit); 70 71static inline unsigned char ds1286_is_updating(void); 72 73static spinlock_t ds1286_lock = SPIN_LOCK_UNLOCKED; 74 75/* 76 * Bits in rtc_status. (7 bits of room for future expansion) 77 */ 78 79#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */ 80#define RTC_TIMER_ON 0x02 /* missed irq timer active */ 81 82unsigned char ds1286_status; /* bitmapped status byte. */ 83unsigned long ds1286_freq; /* Current periodic IRQ rate */ 84 85unsigned char days_in_mo[] = 86{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; 87 88/* 89 * Now all the various file operations that we export. 90 */ 91 92static ssize_t ds1286_read(struct file *file, char *buf, 93 size_t count, loff_t *ppos) 94{ 95 return -EIO; 96} 97 98static int ds1286_ioctl(struct inode *inode, struct file *file, 99 unsigned int cmd, unsigned long arg) 100{ 101 102 struct rtc_time wtime; 103 104 switch (cmd) { 105 case RTC_AIE_OFF: /* Mask alarm int. enab. bit */ 106 { 107 unsigned int flags; 108 unsigned char val; 109 110 if (!capable(CAP_SYS_TIME)) 111 return -EACCES; 112 113 spin_lock_irqsave(&ds1286_lock, flags); 114 val = CMOS_READ(RTC_CMD); 115 val |= RTC_TDM; 116 CMOS_WRITE(val, RTC_CMD); 117 spin_unlock_irqrestore(&ds1286_lock, flags); 118 119 return 0; 120 } 121 case RTC_AIE_ON: /* Allow alarm interrupts. */ 122 { 123 unsigned int flags; 124 unsigned char val; 125 126 if (!capable(CAP_SYS_TIME)) 127 return -EACCES; 128 129 spin_lock_irqsave(&ds1286_lock, flags); 130 val = CMOS_READ(RTC_CMD); 131 val &= ~RTC_TDM; 132 CMOS_WRITE(val, RTC_CMD); 133 spin_unlock_irqrestore(&ds1286_lock, flags); 134 135 return 0; 136 } 137 case RTC_WIE_OFF: /* Mask watchdog int. enab. bit */ 138 { 139 unsigned int flags; 140 unsigned char val; 141 142 if (!capable(CAP_SYS_TIME)) 143 return -EACCES; 144 145 spin_lock_irqsave(&ds1286_lock, flags); 146 val = CMOS_READ(RTC_CMD); 147 val |= RTC_WAM; 148 CMOS_WRITE(val, RTC_CMD); 149 spin_unlock_irqrestore(&ds1286_lock, flags); 150 151 return 0; 152 } 153 case RTC_WIE_ON: /* Allow watchdog interrupts. */ 154 { 155 unsigned int flags; 156 unsigned char val; 157 158 if (!capable(CAP_SYS_TIME)) 159 return -EACCES; 160 161 spin_lock_irqsave(&ds1286_lock, flags); 162 val = CMOS_READ(RTC_CMD); 163 val &= ~RTC_WAM; 164 CMOS_WRITE(val, RTC_CMD); 165 spin_unlock_irqrestore(&ds1286_lock, flags); 166 167 return 0; 168 } 169 case RTC_ALM_READ: /* Read the present alarm time */ 170 { 171 /* 172 * This returns a struct rtc_time. Reading >= 0xc0 173 * means "don't care" or "match all". Only the tm_hour, 174 * tm_min, and tm_sec values are filled in. 175 */ 176 177 ds1286_get_alm_time(&wtime); 178 break; 179 } 180 case RTC_ALM_SET: /* Store a time into the alarm */ 181 { 182 /* 183 * This expects a struct rtc_time. Writing 0xff means 184 * "don't care" or "match all". Only the tm_hour, 185 * tm_min and tm_sec are used. 186 */ 187 unsigned char hrs, min, sec; 188 struct rtc_time alm_tm; 189 190 if (!capable(CAP_SYS_TIME)) 191 return -EACCES; 192 193 if (copy_from_user(&alm_tm, (struct rtc_time*)arg, 194 sizeof(struct rtc_time))) 195 return -EFAULT; 196 197 hrs = alm_tm.tm_hour; 198 min = alm_tm.tm_min; 199 200 if (hrs >= 24) 201 hrs = 0xff; 202 203 if (min >= 60) 204 min = 0xff; 205 206 BIN_TO_BCD(sec); 207 BIN_TO_BCD(min); 208 BIN_TO_BCD(hrs); 209 210 spin_lock(&ds1286_lock); 211 CMOS_WRITE(hrs, RTC_HOURS_ALARM); 212 CMOS_WRITE(min, RTC_MINUTES_ALARM); 213 spin_unlock(&ds1286_lock); 214 215 return 0; 216 } 217 case RTC_RD_TIME: /* Read the time/date from RTC */ 218 { 219 ds1286_get_time(&wtime); 220 break; 221 } 222 case RTC_SET_TIME: /* Set the RTC */ 223 { 224 struct rtc_time rtc_tm; 225 226 if (!capable(CAP_SYS_TIME)) 227 return -EACCES; 228 229 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, 230 sizeof(struct rtc_time))) 231 return -EFAULT; 232 233 return ds1286_set_time(&rtc_tm); 234 } 235 default: 236 return -EINVAL; 237 } 238 return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0; 239} 240 241/* 242 * We enforce only one user at a time here with the open/close. 243 * Also clear the previous interrupt data on an open, and clean 244 * up things on a close. 245 */ 246 247static int ds1286_open(struct inode *inode, struct file *file) 248{ 249 spin_lock_irq(&ds1286_lock); 250 251 if (ds1286_status & RTC_IS_OPEN) 252 goto out_busy; 253 254 ds1286_status |= RTC_IS_OPEN; 255 256 spin_lock_irq(&ds1286_lock); 257 return 0; 258 259out_busy: 260 spin_lock_irq(&ds1286_lock); 261 return -EBUSY; 262} 263 264static int ds1286_release(struct inode *inode, struct file *file) 265{ 266 ds1286_status &= ~RTC_IS_OPEN; 267 268 return 0; 269} 270 271static unsigned int ds1286_poll(struct file *file, poll_table *wait) 272{ 273 poll_wait(file, &ds1286_wait, wait); 274 275 return 0; 276} 277 278/* 279 * The various file operations we support. 280 */ 281 282static struct file_operations ds1286_fops = { 283 .llseek = no_llseek, 284 .read = ds1286_read, 285 .poll = ds1286_poll, 286 .ioctl = ds1286_ioctl, 287 .open = ds1286_open, 288 .release = ds1286_release, 289}; 290 291static struct miscdevice ds1286_dev= 292{ 293 .minor = RTC_MINOR, 294 .name = "rtc", 295 .fops = &ds1286_fops, 296}; 297 298int __init ds1286_init(void) 299{ 300 printk(KERN_INFO "DS1286 Real Time Clock Driver v%s\n", DS1286_VERSION); 301 misc_register(&ds1286_dev); 302 303 return 0; 304} 305 306static char *days[] = { 307 "***", "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" 308}; 309 310/* 311 * Info exported via "/proc/rtc". 312 */ 313int get_ds1286_status(char *buf) 314{ 315 char *p, *s; 316 struct rtc_time tm; 317 unsigned char hundredth, month, cmd, amode; 318 319 p = buf; 320 321 ds1286_get_time(&tm); 322 hundredth = CMOS_READ(RTC_HUNDREDTH_SECOND); 323 BCD_TO_BIN(hundredth); 324 325 p += sprintf(p, 326 "rtc_time\t: %02d:%02d:%02d.%02d\n" 327 "rtc_date\t: %04d-%02d-%02d\n", 328 tm.tm_hour, tm.tm_min, tm.tm_sec, hundredth, 329 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday); 330 331 /* 332 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will 333 * match any value for that particular field. Values that are 334 * greater than a valid time, but less than 0xc0 shouldn't appear. 335 */ 336 ds1286_get_alm_time(&tm); 337 p += sprintf(p, "alarm\t\t: %s ", days[tm.tm_wday]); 338 if (tm.tm_hour <= 24) 339 p += sprintf(p, "%02d:", tm.tm_hour); 340 else 341 p += sprintf(p, "**:"); 342 343 if (tm.tm_min <= 59) 344 p += sprintf(p, "%02d\n", tm.tm_min); 345 else 346 p += sprintf(p, "**\n"); 347 348 month = CMOS_READ(RTC_MONTH); 349 p += sprintf(p, 350 "oscillator\t: %s\n" 351 "square_wave\t: %s\n", 352 (month & RTC_EOSC) ? "disabled" : "enabled", 353 (month & RTC_ESQW) ? "disabled" : "enabled"); 354 355 amode = ((CMOS_READ(RTC_MINUTES_ALARM) & 0x80) >> 5) | 356 ((CMOS_READ(RTC_HOURS_ALARM) & 0x80) >> 6) | 357 ((CMOS_READ(RTC_DAY_ALARM) & 0x80) >> 7); 358 if (amode == 7) s = "each minute"; 359 else if (amode == 3) s = "minutes match"; 360 else if (amode == 1) s = "hours and minutes match"; 361 else if (amode == 0) s = "days, hours and minutes match"; 362 else s = "invalid"; 363 p += sprintf(p, "alarm_mode\t: %s\n", s); 364 365 cmd = CMOS_READ(RTC_CMD); 366 p += sprintf(p, 367 "alarm_enable\t: %s\n" 368 "wdog_alarm\t: %s\n" 369 "alarm_mask\t: %s\n" 370 "wdog_alarm_mask\t: %s\n" 371 "interrupt_mode\t: %s\n" 372 "INTB_mode\t: %s_active\n" 373 "interrupt_pins\t: %s\n", 374 (cmd & RTC_TDF) ? "yes" : "no", 375 (cmd & RTC_WAF) ? "yes" : "no", 376 (cmd & RTC_TDM) ? "disabled" : "enabled", 377 (cmd & RTC_WAM) ? "disabled" : "enabled", 378 (cmd & RTC_PU_LVL) ? "pulse" : "level", 379 (cmd & RTC_IBH_LO) ? "low" : "high", 380 (cmd & RTC_IPSW) ? "unswapped" : "swapped"); 381 382 return p - buf; 383} 384 385/* 386 * Returns true if a clock update is in progress 387 */ 388static inline unsigned char ds1286_is_updating(void) 389{ 390 return CMOS_READ(RTC_CMD) & RTC_TE; 391} 392 393 394void ds1286_get_time(struct rtc_time *rtc_tm) 395{ 396 unsigned char save_control; 397 unsigned int flags; 398 unsigned long uip_watchdog = jiffies; 399 400 /* 401 * read RTC once any update in progress is done. The update 402 * can take just over 2ms. We wait 10 to 20ms. There is no need to 403 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP. 404 * If you need to know *exactly* when a second has started, enable 405 * periodic update complete interrupts, (via ioctl) and then 406 * immediately read /dev/rtc which will block until you get the IRQ. 407 * Once the read clears, read the RTC time (again via ioctl). Easy. 408 */ 409 410 if (ds1286_is_updating() != 0) 411 while (jiffies - uip_watchdog < 2*HZ/100) 412 barrier(); 413 414 /* 415 * Only the values that we read from the RTC are set. We leave 416 * tm_wday, tm_yday and tm_isdst untouched. Even though the 417 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated 418 * by the RTC when initially set to a non-zero value. 419 */ 420 spin_lock_irqsave(&ds1286_lock, flags); 421 save_control = CMOS_READ(RTC_CMD); 422 CMOS_WRITE((save_control|RTC_TE), RTC_CMD); 423 424 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS); 425 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES); 426 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS) & 0x1f; 427 rtc_tm->tm_mday = CMOS_READ(RTC_DATE); 428 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH) & 0x1f; 429 rtc_tm->tm_year = CMOS_READ(RTC_YEAR); 430 431 CMOS_WRITE(save_control, RTC_CMD); 432 spin_unlock_irqrestore(&ds1286_lock, flags); 433 434 BCD_TO_BIN(rtc_tm->tm_sec); 435 BCD_TO_BIN(rtc_tm->tm_min); 436 BCD_TO_BIN(rtc_tm->tm_hour); 437 BCD_TO_BIN(rtc_tm->tm_mday); 438 BCD_TO_BIN(rtc_tm->tm_mon); 439 BCD_TO_BIN(rtc_tm->tm_year); 440 441 /* 442 * Account for differences between how the RTC uses the values 443 * and how they are defined in a struct rtc_time; 444 */ 445 if (rtc_tm->tm_year < 45) 446 rtc_tm->tm_year += 30; 447 if ((rtc_tm->tm_year += 40) < 70) 448 rtc_tm->tm_year += 100; 449 450 rtc_tm->tm_mon--; 451} 452 453int ds1286_set_time(struct rtc_time *rtc_tm) 454{ 455 unsigned char mon, day, hrs, min, sec, leap_yr; 456 unsigned char save_control; 457 unsigned int yrs, flags; 458 459 460 yrs = rtc_tm->tm_year + 1900; 461 mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */ 462 day = rtc_tm->tm_mday; 463 hrs = rtc_tm->tm_hour; 464 min = rtc_tm->tm_min; 465 sec = rtc_tm->tm_sec; 466 467 if (yrs < 1970) 468 return -EINVAL; 469 470 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400)); 471 472 if ((mon > 12) || (day == 0)) 473 return -EINVAL; 474 475 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr))) 476 return -EINVAL; 477 478 if ((hrs >= 24) || (min >= 60) || (sec >= 60)) 479 return -EINVAL; 480 481 if ((yrs -= 1940) > 255) /* They are unsigned */ 482 return -EINVAL; 483 484 if (yrs >= 100) 485 yrs -= 100; 486 487 BIN_TO_BCD(sec); 488 BIN_TO_BCD(min); 489 BIN_TO_BCD(hrs); 490 BIN_TO_BCD(day); 491 BIN_TO_BCD(mon); 492 BIN_TO_BCD(yrs); 493 494 spin_lock_irqsave(&ds1286_lock, flags); 495 save_control = CMOS_READ(RTC_CMD); 496 CMOS_WRITE((save_control|RTC_TE), RTC_CMD); 497 498 CMOS_WRITE(yrs, RTC_YEAR); 499 CMOS_WRITE(mon, RTC_MONTH); 500 CMOS_WRITE(day, RTC_DATE); 501 CMOS_WRITE(hrs, RTC_HOURS); 502 CMOS_WRITE(min, RTC_MINUTES); 503 CMOS_WRITE(sec, RTC_SECONDS); 504 CMOS_WRITE(0, RTC_HUNDREDTH_SECOND); 505 506 CMOS_WRITE(save_control, RTC_CMD); 507 spin_unlock_irqrestore(&ds1286_lock, flags); 508 509 return 0; 510} 511 512void ds1286_get_alm_time(struct rtc_time *alm_tm) 513{ 514 unsigned char cmd; 515 unsigned int flags; 516 517 /* 518 * Only the values that we read from the RTC are set. That 519 * means only tm_wday, tm_hour, tm_min. 520 */ 521 spin_lock_irqsave(&ds1286_lock, flags); 522 alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM) & 0x7f; 523 alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM) & 0x1f; 524 alm_tm->tm_wday = CMOS_READ(RTC_DAY_ALARM) & 0x07; 525 cmd = CMOS_READ(RTC_CMD); 526 spin_unlock_irqrestore(&ds1286_lock, flags); 527 528 BCD_TO_BIN(alm_tm->tm_min); 529 BCD_TO_BIN(alm_tm->tm_hour); 530 alm_tm->tm_sec = 0; 531} 532